New Radiation Leak in Japan No Threat to U.S.

by Michael Smith Michael Smith North American Correspondent, MedPage Today
August 20, 2013

A new leak in a storage tank at the crippled Fukushima Daiichi nuclear plant in Japan has released some 300 metric tons of water with dangerously high levels of radiation, the plant's operator said Tuesday.

The new leak is considered dangerous to people exposed to the water, the company told reporters -- an hour's exposure, measured about 2 feet away, would lead to five times the annual limit for plant workers.

But the Tokyo Electric Power Co. (TEPCO) said the tainted water has probably not reached the sea, in contrast to continuing leaks reported earlier this month. Even if it had, it's unlikely to have posed much of a threat outside the immediate area, according to Richard Morin, PhD, of the Mayo Clinic in Jacksonville, Fla.

By the time any of the radiation reached the west coast of the U.S., "the dilution (would be) so enormous that it is unlikely that it could be even measured above background," Morin told MedPage Today by email.

"Hence, no health concern," he added.

Nonetheless, the continuing leakage from the plant -- much of it in tainted groundwater that is not captured and reaches the ocean -- has resulted in measurable environmental effects, other researchers have reported.

For instance, investigators led by Nicholas Fisher, PhD, of Stony Brook University in Stony Brook, N.Y., found that Pacific bluefish tuna had elevated levels of radioactive cesium-134 and cesium-137 that could be linked to contamination from Fukushima.

And, if people ate the tuna, the resulting doses would be less than those that arise from "naturally occurring radionuclides in many food items, medical treatments, air travel, or other background sources," they reported.

TEPCO has built thousands of tanks to contain water coming from the damaged reactors, as well as for underground water that seeps into the damaged buildings.

The tanks have leaked before, a company spokesman told reporters, but this is the largest spill yet. Workers were pumping the water to a temporary tank and using absorbent materials to pick up the residue, the company said in a statement.

The Daiichi plant was seriously damaged during an earthquake and tsunami March 11, 2011.

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